If you're rolling downhill - gravity. If you're going along on the flat - the pedalling effort of the rider.
driveshaft
A bike with 4 wheels has 4 wheels.
Yes, it would be possible to turn a regular bike into an exercise bike. The way that this is done, is by mounting the bike at a level where the wheels spin, but the bike does not move. You can do this by welding metal onto the bottom of the bike, and elevating it.
There are different sizes for dirt bike wheels as there are for regular bike wheels.
ENGINE
The wheels on the side of the direction of the turn.
Thin wheels alone isn't enough to identify the bike type. Can be a road bike, bike, a track bike, a TT bike. Even fixies and single-speeds can have thin wheels.
A bike trailer typically has two wheels.
The purpose of the axle on a bike is to connect the wheels to the frame. It allows the wheels to rotate smoothly and supports the weight of the rider and the bike. The axle contributes to the overall functionality of the bicycle by providing stability, enabling the wheels to turn, and supporting the weight of the rider, ensuring a smooth and efficient ride.
The wheels are the big round things on which the bike moves and the axles are at the center of the wheels, attaching them to the bike.
The energy associated with a moving bike is kinetic energy, which is the energy of motion. As the pedals rotate and the wheels turn, the bike gains kinetic energy due to its motion.
Tubular bike wheels offer advantages such as lower rolling resistance, better handling, and reduced risk of pinch flats compared to other types of bike wheels.